Chapter 23 - The Lymphoid System
Terms in this set (28)
3 main functions of lymphoid system
1. surveillance/protection for the recognition and destruction of foreign biological invaders
2. Returns interstitial fluid to the blood to maintain normal fluid balance
3. Absorbs lipids and vitamins A, D, E, K via lymphatic capillaries called lacteals
What specific tissue type is lymph
Where does lymph come from?
filtered blood plasma; interstitial fluid + solutes +bacteria/other stuff
Compare lymphatic and vascular capillaries
Lymphatic capillaries are absent in avascular areas, CNS, and bone marrow. THey have a larger diameter and are fenestrated with thinner walls. One-way valves from overlapping endothelial cells (vascular capillaires don't have one way valves, only some veins)
What are lacteals? What's their function?
lymphatic capillaries in small intestine; absorb lipids and fat-soluble vitamins (A, D, E, K)
Trace the pathway of lipid-absorption tot he R. atrium
lacteals, cisterna chyli, thoracic duct, L. subclavian vein, L. brachiocephalic vein, superior vena cava, r.atrium
What is the diferene between innate and acquired immunity?
Innate: inborn; nonspecific
Acquired: adaptive; specific
Which leukocytes play a role in acquired immunity?
Define antibody-mediated immunity
humoral, uses Ab to carry out responses; Ab secreted by B-cells
Ab molecules onto cell membrane acting as surface receptors for antigens; effective only against extracellular pathogens; most Ab found in blood
Define cell-mediated immunity
immune cell receptor binds to a receptor on target cell; T-cell
defense against intracellular pathogens
When exposed to antigens, B cells differentiate into plasmocytes: secrete soluble antibodies
List 3 types of T-cells
cytotoxic T-cells: destroy virally infected cells by apoptosis
Helper/Suppressor: regulatory; don't directly attack infected cells but coordinate immune response by controling activity of B cells
Memory T cells
What's the difference between lymphoid tissues and lymphoid organs?
lymphoid tissues are not encapsulated; made up of reticular CT with aggregated lymphocytes forming lymphoid nodules embedded in reticular fibers
List the lymphoid nodules
tonsils:back of tongue
peyer's patches: ileumof small intestine
appendix: off cecum
What's the purpose of Peyer's Patches?
control the population of bacteria from colon back into small intestine
What's the specific tissue type surrounding the lymphoid organs?
Dense Irregular Connective Tissue
Which two systems does the thymus belong to?
endocrine and lymphoid
Which lymphoid organ starts decreasing in size after puberty?
Which hormones contribute to the differentiation of lymphoid stem cells into T cells?
What's the function of splenic white pulp?
contains aggregation of T-cells and B-cells
What's the function of splenic red pulp?
removal by nacrophages of abnormal RBC; stores iron from recycles RBC
What's the function of the lymph nodes?
along lymphatic vessels at various intervals; filter and purify lymph before it reaches venous system
Trace the pathway of lymph from afferent lymphatic vessels through lymph nodes out through the efferent lymphatic vessel
afferent lymphatic vessel, capsule, cortex, medulla, cortex, capsule, efferent lymphatic vessel
What portion of the body does the right lymphatic duct drain?
drains right half of body superior to diaphragm
What portion of the body does the thoracic duct drain?
drains body inferior to diaphragm and left side of upper body
Lymph circulation through right lymphatic duct
lymph (from interstitial fluid), lymphatic capillaries, afferent lymphatic vessels, lymph nodes, efferent lymphatic vessels, R. lymphatic duct, R. subclavian vein, R. brachiocephalic vein, superior vena cava
Lymph circulation through thoracic duct
lymph from interstitial fluid, lymphatic capillaries, afferent lymphatic vessels, lymph nodes, efferent lymphatic vessels, Thoracic duct, L. subclavian vein, L. brachiocephalic vein, SVC, R. atrium
Lymph circulation through cisterna chyli (lower limbs, abdominal area)
lymph from interstitial fluid, lymphatic capillaries, afferent lymphatic vessels, lymph nodes, efferent lymphatic vessel, cisterna chyli, thoracic duct, L. subclavian vein, L. brachiocephalic vein, SVC, R. atrium